4Understanding the soil resistance along an embedded anchor chain is imperative for efficient 5 and economic design of an overall mooring system as it determines the magnitude and direction 6 of the load at the padeye of the anchor. The tensioning process of an embedded chain for 7 catenary moorings was modeled using a coupled Eulerian-Lagrangian (CEL) finite element 8 approach simulating the large deformations of the chain as it cuts through the soil to form an 9 inverse catenary. The analyses reveal that the configuration of the embedded chain and the 10 relationship between tension and chain angle at the padeye show excellent agreement with 11 previously published analytical predictions. However, the ratio of the tension at the padeye to 12 that at the mudline obtained from CEL is significantly higher than the theoretical values, mainly 13 due to partial mobilization of the frictional soil resistance along the length of the chain. The 14CEL results indicate that the partial mobilization is a result of the combined-loading effect 15 during failure of the soil around the embedded chain as it cuts through the seabed, in contrast 16 with the conventional assumption that the ultimate frictional and normal soil resistances are 17 mobilized simultaneously. A new design approach is proposed for calculating the local 18 equivalent coefficient of friction based on the yield locus for a deeply embedded chain and the 19 normality rule. 20
An approach for designing the compliant adaptive wing leading edge with composite material is proposed based on the topology optimization. Firstly, an equivalent constitutive relationship of laminated glass fiber reinforced epoxy composite plates has been built based on the symmetric laminated plate theory. Then, an optimization objective function of compliant adaptive wing leading edge was used to minimize the least square error (LSE) between deformed curve and desired aerodynamics shape. After that, the topology structures of wing leading edge of different glass fiber ply-orientations were obtained by using the solid isotropic material with penalization (SIMP) model and sensitivity filtering technique. The desired aerodynamics shape of compliant adaptive wing leading edge was obtained based on the proposed approach. The topology structures of wing leading edge depend on the glass fiber ply-orientation. Finally, the corresponding morphing experiment of compliant wing leading edge with composite materials was implemented, which verified the morphing capability of topology structure and illustrated the feasibility for designing compliant wing leading edge. The present paper lays the basis of ply-orientation optimization for compliant adaptive wing leading edge in unmanned aerial vehicle (UAV) field. ª 2014 Production and hosting by Elsevier Ltd. on behalf of CSAA & BUAA.
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